JSFiddle - React, Tailwind, and code Playground

HTML

<div id="h1">██</div>

JavaScript

var myFunctions = [Red, Green, Blue]

var myFuncIterator = makeIterator(myFunctions)

var i=0, timer = setInterval(()=>{
  var func = myFuncIterator.next()
  if (func.done) clearInterval(timer)
  else func.value()
}, 1000)

function Red() {
  h1.style.color = 'red';
}
function Green() {
  h1.style.color = 'green';
}
function Blue() {
  h1.style.color = 'blue';
}

function makeIterator(array){
  var nextIndex = 0;
  return {
    next: function(){
      return nextIndex < array.length ?
        {value: array[nextIndex++], done: false} :
      {done: true};
    }
  }
}